Enhanced Rotary Dryer Lifter Design Using a Lifter Simulator

Industrial drying may seem like a straightforward process, but in reality, many factors must be considered to create the most effective drying solution that maximizes heat transfer efficiency. The material to be processed, lifter design and pattern should all be taken into account when designing a rotary dryer, and are best determined through testing in a lab setting.

One of many important tools used in such thermal lab tests is the rotary dryer lifter simulator. Often times, before a material runs through the pilot size dryer, it is tested in the lifter simulator to determine the rotations per minute and the lifter pattern needed during the full-scale drying process. The lifter simulator simply mimics the set-up of a full-scale rotary dryer, but unlike the dryer, it is compact in size and does not use a process air to dry the material.

The FEECO simulator consists of a drum with adjustable lifters, with three lifter options available: radial, single bend, and double bend. Each lifter can be constructed of carbon steel, or polished stainless steel. The lifters scoop the material up, carry it over, and drop it as the drum rotates. The falling of the material creates what is known as a “curtain.” In a continuous rotary dryer, the curtain maximizes the heat transfer between the material and the stream of hot process air running through the dryer. The optimum curtain is created from finding the best lifter pattern and design, in combination with rotational speed of the lifter simulator. Our Process Experts are paying particular attention to how the material falls during the drum’s rotation, and analyzing the variables previously noted to create the most ideal drying process. Finally, the curtain produced is evaluated visually in real time, and pictures and video can be taken for later evaluation by our team of Process Experts.

Once the best pattern and speed is determined, our Process Experts can test the specially- designed lifters in our pilot size rotary dryer. In a commercial plant, the lifters are typically welded to the shell. FEECO can bolt the lifters into place as opposed to welding them. This is helpful in cases where an abrasive material needs to be run through the rotary dryer, causing the lifters to wear out quicker than usual. When the lifters are bolted into place, removing them is as simple as taking out the bolts. In a high-maintenance case, this cuts down on cost in time and materials.

While the lifter simulator can be incredibly beneficial to our thermal tests, it is used at the discretion of our experienced Process Experts. Our team has a vast knowledge base of materials, and from this database, we are able to bypass some initial testing phases, saving time and money.

For more information on testing with FEECO’s lifter simulator, download our ebook or contact us today! We look forward to learning more about your industrial drying needs.